Bit-brace



(No Model.)

O. PEGK. BIT BRAGE.

'Patented 0015.20, 1891.

WITNESS@ NITED :STATES PATENT OFFICE.

OBED PECK, OF ROWE, MASSACHUSETTS.

BIT-BRAC E.

SPECIFICATION forming part of Letters Patent No. 461,617, dated October20, 1891.

Application tiled January 13, 1891. Serial No. 377,601. (No model.)

To @ZZ whom it may concern.-

`Be it known that LOBED PECK, of Rowe, in the county of Franklin, Stateof Massachusetts, have invented certain new and useful Improvements inBit-Braces, of which the following is a description sufficiently full,clear, and exact to enable any person skilled in the art or science towhich said invention appertains to make and use the same, referencebeing had lto the accompanying drawings, forming part of thisspecification, in which- Figure 1 is a side elevation of my improvedbit-brace; Fig. 2, a vertical transverse section of the head or rose;Fig. 3, an end elevation of the chuck; Fig. 4, a vertical longitudinalsection of the same, taken between the jaws; Fig. 5, a like View takenthrough the jaws, and Fig. 6 a sectional view showing-'a drillbit inposition in the chuck.

Like letters and figures of reference indicate corresponding parts inthe different figures of the drawings.

My invention relates especially to an improvement in the chuck and roseof bit-braces; and it consists in certain novel features hereinafterfully set forth and claimed, the object being to produce a simpler,cheaper, and more eifective device of this character than is now inordinary use.

The nature and operation of the improvement will be readily understoodby all conversant with such matters from the following explanation. l

The chuck B is secured to one end of the sweep by a pin Z). The body (Zof the chuck is reduced at f, and a sleeve gis fitted to rotate on saidreduced portion in the ordinary manner. Said sleeve is screw-threadedinteriorly at h. Two flaring spring-jaws t' have their innerendsscrew-threaded atj and work in the threaded portion of said sleeve, theheads k of said jaws being interiorly grooved at 1 and adapted to iarefrom the mouth of the chuckwhen projected by the screw in the ordinarymanner. The body d of the chuck is provided centrally with an opening mrectangular in cross-section, and the walls of which converge inwardly,the jaws i working on opposite sides of said socket in the usual manner.This socket is of the ordinary form employed to center a square-headedtool.

In my improvement I extend the socket m into the body of the chuck at p,said extension being circularin horizontal section and having its wallsconverging continuously from the rectangular walls of said socket to apoint q at the bottom. By this construction the chuck may be employedfor holding a round-shank tool or boring-bit, as C, the head of said bitdropping evenlylinto said socket, and when clamped byI the jaws beingfirmly centered thereby, as shown in Fig. 6.

The rose D is mounted as follows: The opposite end of the sweep A iscone-shaped at r, to form a step for said rose. An annular groove t isformed in said sweep. The rosebody 1J is constructed of metal chamberedto receive the sweep-end, and provided interiorly with a seat w forsaidcon e-shaped step. Said body o is provided interiorly with a chamber 15,with which the groove t in the sweep-end registers. An opening 17 leadsthrough said body into said chamber and a similar opening 18 (seeFig. 1) leads into the sweep-socket above said chamber. A wooden head 16is secured to said body by means of brads or projections 19, whichpenetrate said head, and a screw 20, turned into said body and restingin an annular rabbet in said head. The rose is secured in position onthe sweep by means of Babbitt metal 21, which is poured into the chamber15 through the opening 17, and which enters the groove t in said sweep.The duct 18 serves to admit oil to the cone bearing, and the Babbitt 2lforms an additional lubricant for the rose while preventing it frombeing withdrawn from the sweep.

The rose mounted as described, while permitting the sweep to rotatefreely prevents all lateral movement and enables the wear to be readilytaken up by rabbeting.

The circular or cone-shaped socket forms a bearing for the round shankof the tool C and prevents the saine from rocking inv the jaws when inuse, as freq uentlyhappens when such tool is inserted in the ordinaryrectangular IOO jaws, said socket being angular in cross-sec tion in itsouter portion and circular in crosssection in its inner portion andhaving its Walls converging continuously inward, substantially as andfor the purpose set forth.

3. In a bit-brace, the sweep A, having the cone-step 71 and groove t, incombination with the rose D, comprising the body n, chambered at 15, andprovided with the seat w, and brads 19, the wooden head 16, the screw20, turned into said body and projecting into a rabbet in said head, andthe Babbitt metal 2l in said chamber, all being arranged to operatesubstantially as described.

OBED PECK.

fitnessesz O. M. SHAW, K. DURFEE.

